1. Technical Field
The present invention relates to a hermetic compressor used in a freezer, such as a home refrigerator, and to a method of manufacturing the compressor.
2. Background Art
A hermetic motor-driven compressor used in a freezer, such as a home refrigerator, has been demanded to have a small power consumption, small noises, low cost, and high reliability.
FIG. 4 is a sectional view of conventional hermetic compressor 501 described in patent citation 1. Hermetic container 1 accommodates compressing element 2 and motor element 3 therein. The lower portion of hermetic container 1 stores lubricating oil 4. Shaft 6 includes main shaft 7 and eccentric shaft 8. Eccentric shaft 8 of shaft 6 is coupled to piston 10 via connecting rod 9. Main shaft 7 is supported by bearing 11. A lower end of shaft 6 has opening 6A formed therein. Inserting part 12A of oil-feeding pipe 12 is press-fitted and fixed into opening 6A. A tip end of oil-feeding pipe 12 opens to lubricating oil 4. Oil-feeding pipe 12 is formed by press-molding metal.
An operation of hermetic compressor 501 will be described. The rotation of motor element 3 is converted to a reciprocating movement by eccentric shaft 8 and connecting rod 9 of compressing element 2. Connecting rod 9 causes piston 10 to reciprocate in cylinder 2A to compress refrigerant. Motor element 3 rotates shaft 6 to rotate oil-feeding pipe 12. Oil-feeding pipe 12 having the tip end opening to lubricating oil 4 rotates to generate a pressure in oil-feeding pipe 12 by centrifugal pump effects. This pressure causes lubricating oil 4 to be sucked to oil-feeding pipe 12 and supplies the sucked oil to sliding parts of compressing element 2 from a top end of shaft 6.
FIGS. 5A and 5B are enlarged sectional views of shaft 6 and oil-feeding pipe 12 for illustrating a method of assembling shaft 6 and oil-feeding pipe 12. FIG. 5A shows shaft 6 and oil-feeding pipe 12 before assembled. FIG. 5B shows shaft 6 and oil-feeding pipe 12 after assembled. As described above, oil-feeding pipe 12 is formed by press-molding metal. Tip-end outer circumference 12B of inserting part 12A of oil-feeding pipe 12 may not be chamfered, or burrs produced at tip-end outer circumference 12B may not be eliminated adequately. In these cases, when inserting part 12A of oil-feeding pipe 12 is press-fitted into opening 6A of shaft 6, tip-end outer circumference 12B of inserting part 12A of oil-feeding pipe 12 made of metal grinds opening 6A of shaft 6 made of metal, possibly producing fine metal powder 6B.
Fine metal powder 6B is produced after oil-feeding pipe 12 is fixed to shaft 6, and hence, metal powder 6B can hardly be removed completely even upon being cleaned, thus remaining inside opening 6A of shaft 6. Fine metal powder 6B which remains is carried to the sliding parts of compressing element 2 together with lubricating oil 4 flowing in direction 501A when compressor 501 operates. Fine metal powder 6B caught in the sliding parts of compressing element 2 may stop compressor 501.    Patent Citation 1    Japanese Patent Laid-Open Publication No. 2001-317460